Bump version in plugin header

Author: ironprogrammer

classic-editor.php

@@ -5,7 +5,7 @@
  * Plugin Name: Classic Editor
  * Plugin URI:  https://wordpress.org/plugins/classic-editor/
  * Description: Enables the WordPress classic editor and the old-style Edit Post screen with TinyMCE, Meta Boxes, etc. Supports the older plugins that extend this screen.
- * Version:     1.6.5
+ * Version:     1.6.6
  * Author:      WordPress Contributors
  * Author URI:  https://github.com/WordPress/classic-editor/
  * License:     GPLv2 or later